JP5364214B2 - Steamed shellfish production method by steaming clams - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide safe oyster having a small risk of causing norovirus food poisoning while inhibiting lowering of deliciousness/texture/appearance of oyster. <P>SOLUTION: A method for producing steamed shellfish by steaming bivalve shucked shellfish includes a step of steaming the bivalve shucked shellfish, using steam at a temperature of not less than 100&deg;C and a pressure of not more than 1 kgf/cm<SP POS="POST">2</SP>G. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  TECHNICAL FIELD The present invention relates to a method for producing steamed shellfish obtained by steaming clams of bivalves, a food processing apparatus used in the production method, and a steamed shellfish obtained by the production method.

  FIG. 1 is a production process diagram for explaining hygiene management in a known oyster production / processing process. In this way, producers, fishermen / fishery cooperatives, etc. generally use sanitary water for cleaning and sterilization in the processing of peeled and packaged oysters during the production and shipment of oysters. We have been working on product management from day to day by raising livestock for a certain period of time using clean seawater. In addition to these efforts, the main production prefectures have established their own proper aquaculture guidelines, norovirus countermeasure guidelines, etc., and the prefectures and producers have collaborated to ensure the safety and reliability of cultured oysters.

  As part of these activities, producers, fishermen's associations, fishery cooperatives, etc. conduct regular self-inspections on shipped cultured oysters to confirm the presence of norovirus. In addition to the self-inspection of producers, prefectures also conduct inspections as necessary. In particular, cultured oysters shipped for raw consumption are not shipped for raw consumption if the result of the test is positive based on the Norovirus countermeasure guidelines and the like. For this reason, even raw oysters are rarely the source of norovirus infection.

  In fact, according to the Ministry of Health, Labor and Welfare, past norovirus food poisoning survey results indicate that it is difficult to detect viruses directly from foods, and about 70% of food poisoning cases indicate that the causative food cannot be identified. Yes. In many cases, food is contaminated through food handlers infected with viruses. For example, looking at the number of foods that cause norovirus food poisoning by the Ministry of Health, Labor and Welfare, the number of cases of bivalve mollusc out of 303 total cases in 2008 is only 20. According to the Ministry of Health, Labor and Welfare, food poisoning caused by bivalves contaminated with norovirus is caused by raw or under-heated foods.

  However, excessive reporting by the mass media, including television, has spread the misconception that some consumers are the main cause of norovirus food poisoning, and if it is heated enough at home, The consumption of oysters, which is safe to eat, is adversely affected. As a result, there is an increasing demand for safe oysters with low risk of norovirus food poisoning among distributors and consumers.

  For example, in Patent Document 1, after cleaning raw oysters peeled from oyster shells, heating the raw oysters at a temperature between 75 ° C. and 80 ° C. for 1 minute to 3 minutes, The surface layer of raw oysters is subjected to coagulation and denaturation treatment, quickly cooled by heat radiation, and then fried in oil with a garment, coating the surface of the oyster by evaporating the moisture in the garment and hardening the starch. Techniques for forming layers and rapidly freezing them are described.

  In Patent Document 2, the frozen oyster is heated and defrosted using superheated steam, and the thawing oyster is heated using far-infrared rays to raise the center temperature to a predetermined temperature or higher and roast it. The technique of baking is described.

  Patent Document 3 discloses a technique in which oysters, which are fresh seafood, are directly heated with superheated steam in a temperature range of 160 ° C. to 300 ° C. and in a time range of 180 seconds to 300 seconds, and then frozen. Have been described.

  Further, in Patent Document 4, the raw or frozen oysters are arranged on a net-like or lattice-like tray using an oyster feeder, and the oysters are roasted on a superheated steam-type baking machine. In addition, a grinder equipped with a gas burner or the like grinds each surface of the oyster peel roasted with superheated steam and freezes it with a mesh (net) belt type tunnel freezer.

JP 2000-139420 A JP 2003-339356 A JP 2004-321018 A JP 2009-112210 A

However, the prior art described in the above literature has room for improvement in the following points.
First, since the technique described in Patent Document 1 is a fritter that is fried in oil with a garment, it is difficult to use it in a pot that is the main cooking method for oysters. In addition, since this technique uses steaming and heating, maintaining the temperature at the center of raw oysters at 85 ° C or higher for 1 minute causes excessive heating, especially invertebrate. Even if the water content is 80% or more, only soft organisms seem to be rich, but they respond quickly to all obstacles, especially overheating, which has a large change over time and causes umami components to flow out instantly and thin. However, quality deterioration cannot be avoided, and the yield is also extremely reduced, so there are many defective products, and conversely, there is a problem that the cost increases.

  Secondly, in the technique described in Patent Document 2, thawing oysters are roasted and baked, so that it is difficult to use them for oysters and pots, which are the main cooking methods for oysters. Further, in this technique, since heating is performed with far infrared rays, the temperature at the center of baking is only 65 ° C., and it is difficult to deactivate norovirus.

  Thirdly, in the technique described in Patent Document 3, since the heating is performed directly by superheated steam in the temperature range of 160 ° C. to 300 ° C. and in the time range of 180 seconds to 300 seconds, it is actually contrary to the description in this document. There was a problem in that umami extract was likely to flow out and discoloration of the appearance was likely to occur.

  Fourthly, in the technique described in Patent Document 4, since each surface of the peeled oyster is squeezed, it is difficult to use it for oysters and pots, which are the main cooking methods for oysters. In addition, since superheated steam of 100 ° C to 450 ° C is generated and roasted against oysters, the umami extract is actually likely to flow out and discoloration of the appearance occurs contrary to the description in this document. There was a problem that it was easy.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a safe oyster having a low risk of causing norovirus food poisoning while suppressing a decrease in umami, texture, appearance and the like of the oyster.

According to the present invention, a method for producing steamed mussels by steaming clams of bivalves, the step of steaming the clams of bivalves using steam at a temperature of 100 ° C. or higher and a pressure of 1 kgf / cm ² G or lower. A production method is provided.

According to this method, since the low-temperature and low-pressure high-humidity steam having a temperature of 100 ° C. or higher and a pressure of 1 kgf / cm ² G or less is used, the ratio of the latent heat amount to the sensible heat amount contained in the saturated water vapor is increased, and the efficiency is improved in a short time. Boiled clams can be steamed evenly and uniformly. Therefore, the center temperature of the clams can be raised in a short time compared with the case where conventionally known high-temperature and high-pressure dry steam is used. Therefore, norovirus can be inactivated in a short time, and the surface temperature of the bivalve is less likely to be heated excessively compared to the center temperature during that time, thus suppressing deterioration of oyster's umami, texture, appearance, etc. be able to.

  Moreover, according to this invention, the steamed shell produced using said production method is provided.

Since this steamed shellfish is steamed using low-temperature and low-pressure, high-humidity steam having a temperature of 100 ° C. or higher and a pressure of 1 kgf / cm ² G or less, the ratio of the latent heat amount to the sensible heat amount contained in the saturated water vapor is large and short. Steamed efficiently and uniformly over time. Therefore, the center temperature of the clams of the bivalve increases in a short time compared to the case of using conventionally known high-temperature and high-pressure dry steam. For this reason, norovirus is deactivated in a short time, and the surface temperature of the bivalve is less likely to be heated excessively compared to the center temperature, so that steamed mussels with less deterioration in umami taste, texture and appearance are obtained.

  Moreover, according to this invention, the manufacturing apparatus of the steamed shell for steaming the clam of a bivalve shell is provided. Here, the steamed shell manufacturing apparatus includes a boiler that supplies high-pressure steam, a steam changer that converts high-pressure steam into reduced-pressure steam, a steamer that steams bivalve debris using reduced-pressure steam, a boiler, and the steam changer. A high-pressure steam pipe for connecting the steam generator, a reduced-pressure steam pipe for connecting the steam changer and the steamer, and a mesh belt for transporting the clams of the clams. The steam changer is configured such that when the high-pressure steam is supplied into a water storage tank provided in the steam changer, water in the water storage tank boils to generate reduced-pressure steam. The reduced pressure steam pipe has an inner diameter larger than the inner diameter of the high pressure steam pipe. Furthermore, this steamer continuously steams the clams of the bivalve by injecting steam from above and below to the clams of the bivalves conveyed on a mesh belt provided to move in the steamer. For having a steam outlet.

  According to this steamed shell manufacturing apparatus, the high-pressure steam supplied from the boiler to the steam changer via the high-pressure steam pipe is supplied into the water storage tank provided in the steam changer, so that Water is boiled and vacuum is generated. The reduced-pressure steam is supplied to the steamer via the reduced-pressure steam pipe having an inner diameter larger than the inner diameter of the high-pressure steam pipe, and is moved on the mesh (net) belt provided to move in the steamer. It is sprayed from the steam outlet of the steamer provided in the vertical direction with respect to the peeled clams being conveyed, and the clams of the clams can be continuously steamed.

  That is, according to this steamed shell manufacturing apparatus, since the low-temperature and low-pressure, high-humidity steam decompressed by the steam changer is used, the ratio of the latent heat amount to the sensible heat amount contained in the saturated steam is increased, and it is efficient and uniform in a short time. Boiled clams can be steamed. Therefore, the center temperature of the clams can be raised in a short time compared with the case where conventionally known high-temperature and high-pressure dry steam is used. Therefore, norovirus can be inactivated in a short time, and the surface temperature of the bivalve is less likely to be heated excessively compared to the center temperature during that time, thus suppressing deterioration of oyster's umami, texture, appearance, etc. be able to.

  According to the present invention, steamed bivalve debris is steamed using low-temperature and low-pressure, high-humidity steam, so that norovirus can be deactivated in a short time, and the oyster's umami, texture, appearance, and the like are reduced. Can be suppressed.

It is a manufacturing-process figure for demonstrating the hygiene management in the production and processing process of a conventionally well-known oyster. It is a manufacturing-process figure for demonstrating the production method of the steamed shell which concerns on embodiment. It is the conceptual diagram which showed the structure of the manufacturing apparatus of the steamed shell which concerns on embodiment. It is a conceptual diagram for demonstrating the mechanism of pressure reduction in the steam changer provided in the manufacturing apparatus of the steamed shell which concerns on embodiment. It is the conceptual diagram which showed the structure of the modification of the manufacturing apparatus of the steamed shell which concerns on embodiment. It is TV figure which shows the state change of water-steam. It is a graph which shows the measurement data of the core temperature of the stripped oyster after the steam of Experimental example 1. It is a photograph for demonstrating the mode of the operation | work of the steaming process and the freezing process of the oyster flakes of Experimental example 1. It is a photograph for demonstrating the appearance of the oyster peeling in the steaming process and freezing process of the oyster peeling of Experimental Examples 1-4. It is a photograph for demonstrating the mode of sensory evaluation of the steamed oyster of Experimental example 5. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate. Hereinafter, the unit of pressure is represented by [kg / cm ² ], which is the force [kg] acting on the unit area [cm ² ]. Here, the last G means a gauge pressure, which is a pressure based on the atmospheric pressure “instructed by the pressure gauge”, and therefore gauge pressure = absolute pressure−atmospheric pressure.

<Types of bivalves>
In the present embodiment, “Bivalvia” means an animal belonging to a clam class that is a group of mollusks. Moreover, as a shellfish used by this embodiment, the shellfish which belongs to the oyster eye among the shellfish which belongs to this bivalve rope is preferable. Furthermore, as the shellfish used in the present embodiment, among the shellfish belonging to the oyster order, the shellfish belonging to the lobster family is preferable. And as a shellfish used by this embodiment, the shellfish which belongs to the genus Magaki or the genus Itabaki is preferable among the shellfish which belongs to the family Itabaki.

  Here, as a shellfish which belongs to the genus oyster, for example, oyster (true oyster), oyster oyster (rock oyster), sminoe oyster (Suminoe oyster) and the like are preferably used. Moreover, as a shellfish which belongs to the genus Itabaki, for example, a lobster (bamboo oyster) or a European oyster is preferably used. Because, in addition to the growing demand for safe oysters with low risk of norovirus food poisoning, the technology for heat treatment without losing the umami extract and without reducing the appearance and texture is related to oysters. This is because the technology of the present embodiment can be applied particularly suitably to solve these problems.

<Vapor properties>
In the present embodiment, “steam” means a gas containing water vapor. That is, the “steam” includes a gas containing water vapor and water particles dispersed therein.

  Steam is a colorless and transparent gas (gas) generated by heating water. The energy that raises water to the boiling point is called sensible heat, and the energy that changes boiling water into steam is called latent heat. These calorific values show different values depending on pressure and temperature conditions. During the change of latent heat, the steam contains moisture and is called “wet steam”. Steam that has completely evaporated water is called “saturated steam”, and “superheated steam” is what continues to add heat. The steam immediately after leaving the boiler is “saturated steam”, and the saturated steam generates condensed water with slight heat dissipation.

  Here, as shown in the saturated steam table shown below, the present inventors pay attention to the fact that the latent heat increases with decreasing temperature and pressure in the “saturated steam”, not the sensible heat of “wet steam”. The idea is to use the latent heat to steam the clams of the bivalves, and the steam immediately after leaving the boiler dares to pass through the water to reduce the pressure and reduce the temperature, and then the “muscular steam” that contains a lot of latent heat. When sprayed from above and below on the debris, it succeeded in raising the temperature of the central part of the bivalve debris efficiently in a short time compared to the steam immediately after leaving the boiler, and the appearance and texture change The present invention was completed by recognizing that the umami extract was less likely to flow out. That is, the present inventors tend to have the idea of increasing the temperature and pressure of “wet steam” in order to increase the temperature of the central part of the clam debris in a short time if it is a normal idea. However, it can be said that an unexpected effect was obtained by trying the opposite.

<Method of producing steamed shellfish>
FIG. 2 is a production process diagram for explaining a method for producing steamed shellfish according to the embodiment. As shown in this figure, specifically, when a series of operations is started, first, high-pressure steam is generated by a boiler (S102). Then, the high-pressure steam is decompressed by a steam changer to obtain decompressed steam (S104). Subsequently, the debris of the bivalve is steamed using this reduced pressure steam (S106). At that time, after the central temperature of the bivalve debris reaches 85 ° C. so as to surely deactivate the norovirus, the state where the central temperature is 85 ° C. or higher is maintained for 1 minute or longer (S108). Thereafter, the peeled off clams are frozen (S110). Thus, a series of manufacturing steps is completed.

In other words, the method for producing steamed shellfish obtained by steaming clams of bivalves according to this embodiment includes a step of steaming clams of clams using steam at a temperature of 100 ° C. or higher and a pressure of 1 kgf / cm ² G or lower. According to this method, since the low-temperature and low-pressure high-humidity steam having a temperature of 100 ° C. or higher and a pressure of 1 kgf / cm ² G or less is used, the ratio of the latent heat amount to the sensible heat amount contained in the saturated water vapor is increased, and the efficiency is improved in a short time. Boiled clams can be steamed evenly and uniformly. Therefore, the center temperature of the clams can be raised in a short time compared with the case where conventionally known high-temperature and high-pressure dry steam is used. Therefore, norovirus can be inactivated in a short time, and the surface temperature of the bivalve is less likely to be heated excessively compared to the center temperature during that time, thus suppressing deterioration of oyster's umami, texture, appearance, etc. be able to.

  FIG. 3 is a conceptual diagram illustrating a configuration of a steamed shell manufacturing apparatus according to the embodiment. The steamed shell manufacturing apparatus 1000 for steaming the clams of bivalves according to this embodiment includes a boiler 102 that supplies high-pressure steam, a steam changer 106 that converts high-pressure steam into reduced-pressure steam, and a bivalve shell using reduced-pressure steam. And a steamer 110 for steaming the debris. The steamed shell manufacturing apparatus 1000 also conveys the high pressure steam pipe 104 connecting the boiler 102 and the steam changer 106, the decompression steam pipe 108 connecting the steam changer 106 and the steamer 110, and the clam debris 120. A mesh belt 118.

  Here, the reduced pressure steam pipe 108 has an inner diameter larger than the inner diameter of the high pressure steam pipe 104. In addition, the steamer 110 peels off the bivalve by injecting steam 124a and 124b from above and below to the bivalve debris 120 conveyed on the mesh belt 118 provided to move in the steamer 110. Steam outlets 122a and 122b for continuously steaming the body 120 are provided.

  FIG. 4 is a conceptual diagram for explaining a mechanism of pressure reduction in a steam changer provided in the steamed shell manufacturing apparatus according to the embodiment. As described above, the steam changer 106 is supplied with the high-pressure steam 204 into the water storage tank 208 provided in the steam changer 106, whereby the water 202 in the water storage tank 208 boils and the reduced-pressure steam 206. Is configured to occur. At this time, the volume of the steam is significantly expanded by depressurizing the high-pressure steam 204 to become the decompressed steam 206, but the decompressed steam pipe 108 has an inner diameter larger than the inner diameter of the high-pressure steam pipe 104. Circulates in the reduced pressure steam pipe 108 without any problem.

That is, the reduced-pressure steam 206 having a temperature of 100 ° C. or higher and a pressure of 1 kgf / cm ² G or lower is obtained by boiling water 202 in the steam changer 106 using high-pressure steam generated in the boiler. Can do. At this time, the temperature and pressure of the high-pressure steam 204 before being depressurized are not particularly limited, but for example, a temperature of 100 ° C. or higher and a pressure of 3 kgf / cm ² G or higher are preferable. In many cases, the temperature and pressure of the high-pressure steam 204 supplied from the business boiler 102 installed in a normal food factory is 100 ° C. or higher and 3 kgf / cm ² G or higher. This is because it is possible to efficiently generate a large amount of reduced-pressure steam 206 having a temperature of 100 ° C. or higher and a pressure of 1 kgf / cm ² G or lower in the steam changer 106.

The temperature of the high-pressure steam 204 may be 110 ° C. or higher, 120 ° C. or higher, 130 ° C. or higher, 140 ° C. or higher, or 150 ° C. or higher. This is because the higher the temperature of the high-pressure steam 204, the more efficiently and a large amount of reduced-pressure steam 206 having a temperature of 100 ° C. or more and a pressure of 1 kgf / cm ² G or less can be generated in the steam changer. However, the temperature of the high-pressure steam 204 may be 300 ° C. or lower or 200 ° C. or lower because of problems in the capacity of the boiler 102 and cost performance. On the other hand, the pressure of the high pressure steam 204, 4 kgf / cm ² G or more, 5 kgf / cm ² G or more, 6 kgf / cm ² G or more, 7 kgf / cm ² G or more, 8 kgf / cm ² G or more, 9 kgf / ^cm 2 G The above or 10 kgf / cm ² G or more may be used. This is because the higher the pressure of the high-pressure steam 204, the more efficiently and a large amount of reduced-pressure steam 206 having a temperature of 100 ° C. or more and a pressure of 1 kgf / cm ² G or less can be generated in the steam changer 106. However, the pressure of the high-pressure steam 204 may be 30 ° C. kgf / cm ² G or less or 20 kgf / cm ² G or less because of problems in the capacity and cost performance of the boiler 102.

Here, the temperature of the reduced-pressure steam 206 used when steaming the clams 120 is not particularly limited as long as the temperature is 100 ° C. or higher and 1 kgf / cm ² G or lower. However, the upper limit of the temperature of the reduced-pressure steam 206 is preferably 105 ° C. or lower, more preferably 104 ° C. or lower, 103 ° C. or lower, 102 ° C. or lower, or 101 ° C. or lower. This is because the amount of latent heat of saturated water vapor increases as this temperature approaches 100 ° C.

Further, the lower limit of the pressure of the reduced-pressure steam 206 is 0 kgf / cm ² G or more of 1 atmospheric pressure or more in the case of a manufacturing facility provided at an altitude of about zero meters above sea level. Further, the upper limit of the pressure of the reduced pressure steam 206 may be 1 kgf / cm ² G or less, and is not particularly limited. However, the upper limit of the pressure of the vacuum vapor 206, 0.9kgf / cm ² G or less, 0.8 kgf / cm ² G or less, 0.7 kgf / cm ² G or less, 0.6 kgf / cm ² G or less, 0 .5kgf / cm ² G or less, 0.4kgf / cm ² G or less, 0.3kgf / cm ² G or less, 0.2kgf / cm ² G or less, 0.1kgf / cm ² G or less, 0.09kgf / cm ² G below, 0.08kgf / cm ² G or less, 0.07kgf / cm ² G or less, 0.06kgf / cm ² G or less, 0.05 kgf / cm ² G or less, 0.04kgf / cm ² G or less, 0. 03kgf / cm ² G or less, preferably not more than 0.02 kgf / cm ² G or less or 0.01kgf / cm ² G. This is because the amount of latent heat of saturated water vapor increases as the pressure of the reduced-pressure steam 206 approaches 0 kgf / cm ² G.

  Further, at this time, the supply amount of the reduced-pressure steam 206 is not particularly limited and can be appropriately adjusted according to the purpose of food processing. For example, the steam amount of 0.1 kg per 1 kg of clam debris It is preferable to steam the clams 120 using steam of / h or more. That is, the supply amount of the reduced pressure steam 206 is more preferably 0.1 kg / h or more, 0.2 kg / h or more, 0.3 kg / h or more per 1 kg of clam debris. This is because the rate of increase in the center temperature of the clam 120 is increased as the supply amount of the reduced-pressure steam 206 is increased. Further, although the upper limit of the supply amount of the reduced-pressure steam 206 is not particularly determined, the steam amount per kg of clams of the clam shell is 10 kg / h or less, 1 kg / h or less, or 0 due to the problem of the capacity of the production facility and the cost performance. It is preferably 5 kg / h or less.

  Further, at this time, the method of exposing the reduced pressure steam 206 to the clams 120 is not particularly limited. For example, the steam may be injected from one direction, and the reduced pressure steam 124a from two opposite directions may be injected. 124b may be injected, or the reduced-pressure steam may be uniformly injected from the whole so as to surround the top, bottom, left, and right. However, among these, it is preferable to inject the reduced pressure steams 124a and 124b from two opposite directions from the viewpoint of easy design of manufacturing equipment, good cost performance, and heating efficiency of the central part of the clam shell 120. That is, when steaming the bivalve debris 120, the bivalve debris 120 is continuously formed by spraying steam from below onto the bivalve debris 120 conveyed on the mesh belt 118. Steaming is preferred.

  Here, as for the temperature and time of inactivation of norovirus, since the method of increasing this virus in cultured cells has not been established at present, the exact value has not been determined, but in the investigation report of the Ministry of Health, Labor and Welfare Assuming from similar viruses, if the food is heated at a central temperature of 85 ° C. or higher for 1 minute or longer, the infectivity is lost. For this reason, when steaming the bivalve flesh 120, it is preferable to maintain a state where the central temperature of the bivalve flake 120 is 85 ° C. or higher for 1 minute or longer. However, the center temperature of the clam 120 may be raised to 90 ° C. or higher and 95 ° C. or higher. This is because the infectivity of norovirus existing in the bivalve strips 120 becomes easier as the center temperature of the bivalve strips 120 increases. However, it is preferable that the center temperature of the clams 120 is 200 ° C. or lower, 150 ° C. or lower, or 100 ° C. or lower. This is because if the central temperature of the clam 120 is raised too much, it will be heated too much, and the taste of the clam 120 may be lost or the texture may be changed.

  In addition, the state where the center temperature of the clam 120 is not less than 85 ° C. may be maintained for 2 minutes or more, 3 minutes or more, 4 minutes or more, 5 minutes or more. This is because the infectivity of norovirus contained in the bivalve strips 120 becomes easier as the state in which the center temperature of the bivalve strips 120 is 85 ° C. or longer lasts longer. However, the state where the center temperature of the clam 120 is not less than 85 ° C. is preferably within 1 hour, within 30 minutes or within 10 minutes. If the state where the center temperature of the clam 120 is above 85 ° C. is too long, it will be overheated and the taste of the clam 120 may be lost or the texture may change. Because there is.

<Modification including freezing process>
FIG. 5 is a conceptual diagram illustrating a configuration of a modified example of the steamed shell manufacturing apparatus according to the embodiment. Since this steamed shell manufacturing apparatus 1100 has basically the same configuration as the steamed shell manufacturing apparatus 1000 described above, the description of the same configuration is omitted. Hereinafter, the specific points of the steamed shell manufacturing apparatus 1100 will be described.

  The steamed shell manufacturing apparatus 1100 according to the present embodiment, in addition to the configuration of the steamed shell manufacturing apparatus 1000, further supplies a refrigerator 112 for freezing the steamed shellfish and chlorofluorocarbon to the refrigerator 112. A chlorofluorocarbon supply unit 114. The refrigerator 112 is supplied with cold air 128a and 128b cooled by chlorofluorocarbon from above and below with respect to the bivalve debris 120 conveyed on the steel belt 119 provided to move in the refrigerator 112. Cold air outlets 126a and 126b are provided for continuously freezing the clams 120 by spraying.

  Therefore, in this embodiment, the steamed shell obtained in the above embodiment can be suitably frozen. At this time, it is preferable that the step of freezing the steamed shell includes the step of freezing the clam 120 of bivalve using cold air of −20 ° C. or lower. The temperature of the cold air when freezing the steamed shellfish is not particularly limited, but may be, for example, −30 ° C. or lower and −40 ° C. or lower. This is because the lower the temperature of the cold air exposed to the clams 120, the more efficiently the steamed shell can be frozen in a short time. However, from the viewpoint of the capacity of the refrigerator 112 and cost performance, the temperature of the cold air exposed to the clams 120 may be −100 ° C. or higher or −80 ° C. or higher.

  At this time, the method of exposing the cool air to the clams 120 is not particularly limited. For example, the cool air may be sprayed from one direction, or the cool air 128a and 128b are sprayed from two opposite directions. Alternatively, the cool air may be sprayed uniformly from the whole so as to surround the top, bottom, left, and right front and back. However, among these, it is preferable to inject the cold air freons 128a and 128b from two opposite directions from the viewpoint of the ease of designing the manufacturing equipment, the cost performance, and the cooling efficiency of the central part of the clam 120. That is, as a step of freezing the bivalve debris 120, the bivalve debris 120 is continuously frozen by injecting cold air from above and below the bivalve debris 120 conveyed on the steel belt 119. It is preferable.

  Here, when freezing the bivalve strips 120, it is preferable to maintain a state where the central temperature of the bivalve strips 120 is −10 ° C. or lower for 1 minute or longer. However, the center temperature of the bivalve flakes 120 may be cooled to −20 ° C. or lower and −30 ° C. or lower. This is because the lower the center temperature of the bivalve flesh 120, the easier it is for the bivalve flake 120 to freeze in a short time. However, it is preferable that the center temperature of the clam 120 is a −70 ° C. or higher or −60 ° C. or higher. This is because if the central temperature of the clam 120 is excessively cooled, it may take too much time to defrost the clam 120 and the texture may change.

  In addition, if the core temperature of the bivalve flesh 120 freezes the flesh, once it is cooled to -10 ° C or lower, -20 ° C or lower, -30 ° C or lower, the temperature is maintained until it is thawed. Is preferred. This is because it is important to maintain the quality of frozen products by reducing the temperature change.

  As mentioned above, although embodiment of this invention was described with reference to drawings, these are the illustrations of this invention, Various structures other than the above are also employable.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to these.

<Experimental example 1>
Experiments were actually performed on steamed oysters under various conditions using the steamed shell manufacturing apparatus 1100 shown in FIG. Specifically, as shown in Tables 2 and 3 below, Experimental Example 1 (Product 1) was made by placing a oyster stripped from Hiroshima on a mesh belt 118 passing through the interior of the steamer 110. Then, the steaming process was performed by supplying high-pressure steam of 130 ° C. and 5-6 kgf / cm ² G generated from the boiler 102 to the steamer 110 as it is at a steam amount of 0.4 kg / h per 1 kg of oysters. At that time, it took 16 minutes and 25 seconds when the time taken to maintain the state of 85 ° C. for 1 minute after the temperature of the central part of the oyster flake 120 reached 85 ° C. was measured. The measurement data of the core temperature after steaming at that time are shown in FIG. After that, the oyster strips 120 that had undergone this steaming step were put into the refrigerator 112 by the steel belt 119 and frozen for 11 minutes. At that time, cold air of −50 ° C. cooled with chlorofluorocarbon was sprayed from above and below. The results are shown in Table 3, FIG. 8 and FIG. As a result, the yield of the weight after freezing (D) / weight after washing (B) was 80.8%, and it was found that a large amount of umami extract was flowing out from the oyster strips 120. In addition, when a plurality of functional panelists with sufficient training were observed with the naked eye, the oyster flake 120 was discolored yellow and the appearance was deteriorated. Further, when these sensory panelists actually tried, the deterioration of the texture and taste of the oyster flake 120 was significant.

<Experimental example 2>
An experiment similar to Experimental Example 1 was performed using Hyogo oysters instead of Hiroshima oysters. The results are shown in Table 3, FIG. 8 and FIG. As a result, it took 15 minutes and 45 seconds to measure the time taken to maintain the state of 85 ° C. for 1 minute after the temperature at the center of the oyster flake 120 reached 85 ° C. In addition, the yield of the weight after freezing (D) / weight after washing (B) was 75.3%, and it was found that a large amount of umami extract was flowing out from the oyster strips 120. In addition, when a plurality of functional panelists with sufficient training were observed with the naked eye, the oyster flake 120 was discolored yellow and the appearance was deteriorated. Further, when these sensory panelists actually tried, the deterioration of the texture and taste of the oyster flake 120 was significant.

<Experimental example 3>
An experiment similar to Experimental Example 1 was performed with the heating time of the steaming process fixed at 6 minutes. The results are shown in Table 3, FIG. 8 and FIG. As a result, the temperature at the center of the oyster flake 120 increased only to 73.2 ° C. to 77.0 ° C. after 6 minutes. Therefore, norovirus inactivation may be insufficient. The yield of the weight after freezing (D) / weight after washing (B) was 88.1%, and it was found that the flow of many umami extracts from the oyster strips 120 was suppressed. In addition, when a plurality of functional panelists with sufficient training were observed with the naked eye, the oyster flake 120 was hardly discolored and the appearance was good. Furthermore, when these sensory panelists actually tried, the texture and taste of the oyster strips 120 were good.

<Experimental example 4>
The same experiment as in Experimental Example 1 was conducted. A high-pressure steam of 130 ° C. and 5 to 6 kgf / cm ² G generated from the boiler 102 was once converted into a reduced-pressure steam of 100 ° C. and 0 to 0.07 kgf / cm ² G through the steam changer 106. Then, the steaming process was performed by supplying steam to the steamer 110 at a steam amount of 0.4 kg / h per 1 kg of oyster strips. The results are shown in Table 3, FIG. 8 and FIG. As a result, the temperature at the center of the oyster flake 120 rose to 85.7 ° C. to 87.5 ° C. after 6 minutes, and was further heated for 1 minute. Therefore, inactivation of norovirus is considered sufficient. The yield of the weight after freezing (D) / the weight after washing (B) was 84.2%, and it was found that the flow of many umami extracts from the oyster strips 120 was suppressed. In addition, when a plurality of functional panelists with sufficient training were observed with the naked eye, the oyster flake 120 was hardly discolored and the appearance was good. Furthermore, when these sensory panelists actually tried, the texture and taste of the oyster strips 120 were good.

<Experimental example 5>
Experiments similar to Experimental Example 1 were performed on high pressure steam (130 ° C., 5-6 kgf / cm ² G) and low pressure steam (100 ° C., 0-0. 07kgf / cm ² G) was used to supply the steam at a rate of 0.4 kg / h per 1 kg of oyster strips to perform the steaming process. At that time, the heating was continued until the temperature of the central part of the oyster flake 120 reached 85 ° C. and maintained at 85 ° C. for 1 minute. In particular, the freezing process was not performed. Thereafter, the yield was calculated by comparing the change in the total weight of the oysters before and after the steaming process. The results are shown in Table 4.

  As a result, the yield of the weight after the steaming process / the weight before the steaming process was in the range of 75 to 100% in all cases, and there was no significant difference in the yield between the low pressure steam and the high pressure steam. For some raw oysters, the yield was calculated by comparing the individual weight changes of the oysters before and after the steaming process. As a result, the yield of the weight after the steaming process / the weight before the steaming process is within the range of 75 to 100% in each case even in terms of individual weight, and the yield is large in the case of low pressure steam and in the case of high pressure steam. There was no difference.

  In addition, for these raw oysters, high pressure steam-treated oysters, and low-pressure steam-treated oysters, two samples were selected for each and tested for nutritional components. In addition, as a method for inspecting the nutritional component, the inspection was conducted by an official method based on the nutrition labeling standard. The results are shown in Table 5.

  As a result, compared to raw oysters, the high-pressure steam-treated oysters and the low-pressure steam-treated oysters showed a slight decrease in moisture, while protein, heat, zinc, and glycogen increased significantly. It was. However, there was no significant difference in moisture, protein, calorie, zinc and glycogen between high pressure steamed oysters and low pressure steamed oysters. As for taurine, no significant difference was observed among raw oysters, high-pressure steam-treated oysters, and low-pressure steam-treated oysters.

  Moreover, about the said Okayama raw oyster, the high pressure steam-treated oyster, and the low pressure steam-treated oyster, several sensory panelists (10 persons) with abundant experience actually tasted and taste-evaluated. The results are shown in Table 6 and FIG.

  As a result, as shown in Table 5, there was no significant difference in moisture, protein, calorie, zinc, glycogen, and taurine between the high pressure steamed oyster and the low pressure steamed oyster, It turned out that there was an unexpectedly big difference in taste. In other words, the oysters treated with high-pressure steam had a feeling that the body was papasa, the taste was light, and the oyster body stuck to the teeth and remained on the teeth (perhaps the surface of the oysters was thought to be dry). On the other hand, the oysters treated with low-pressure steam were juicy, rich in taste and remained umami, sweet, fluffy, fluffy and soft, with a lot of gravy and a persistent aftertaste. Such sensory test results were repeated, but were difficult to predict from the nutritional component test results shown in Table 5 above.

<Consideration of results>
From the experimental results of the above experimental examples 1 to 4, if a low-temperature and low-pressure high-humidity steam having a temperature of 100 ° C. or higher and a pressure of 1 kgf / cm ² G or less is used, the ratio of the latent heat amount to the sensible heat amount contained in the saturated water vapor is large. It turns out that it is possible to steam the bivalve strips efficiently and uniformly in a short time. Therefore, the center temperature of the clams can be raised in a short time compared with the case where conventionally known high-temperature and high-pressure dry steam is used. Therefore, norovirus can be inactivated in a short time, and the surface temperature of the bivalve is less likely to be heated excessively compared to the center temperature during that time, thus suppressing deterioration of oyster's umami, texture, appearance, etc. be able to.

In addition, from the experimental results of Experimental Example 5 above, when using low-temperature and low-pressure high-humidity steam having a temperature of 100 ° C. or higher and a pressure of 1 kgf / cm ² G or less, a conventionally known high-temperature and high-pressure dry steam is used. It was found that steamed oysters that are equivalent in terms of moisture and nutritional components can be obtained. Surprisingly, however, the use of low-temperature and low-pressure, high-humidity steam at a temperature of 100 ° C. or higher and a pressure of 1 kgf / cm ² G or lower is more umami than when a conventionally known high-temperature and high-pressure dry steam is used. In terms of texture, to obtain steamed oysters with unexpectedly excellent characteristics that are juicy, rich in taste, umami remains, sweet, plump and soft, fluffy and rich in gravy and aftertaste is not persistent I found out that

  In the above, this invention was demonstrated based on the Example. It is to be understood by those skilled in the art that this embodiment is merely an example, and that various modifications are possible and that such modifications are within the scope of the present invention.

DESCRIPTION OF SYMBOLS 102 Boiler 104 High pressure steam pipe 106 Steam changer 108 Depressurization steam pipe 110 Steamer 112 Refrigerator 114 Freon supply part 118 Mesh (net) belt 119 Steel belt 120 Bivalve debris 122a, 122b Steam outlets 124a, 124b Steam 126a, 126b Cold air Outlet 128a, 128b Cold air 202 Water 204 High-pressure steam 206 Depressurized steam 208 Water tank 1000 Steamed shell manufacturing apparatus 1100 Steamed shell manufacturing apparatus

Claims (8)

A method for producing steamed oysters by steaming oysters,
By boiling water using high-pressure steam at a temperature of 100 ° C. or higher and a pressure of 3 kgf / cm ² G or higher, a temperature of 100 ° C. or higher and 105 ° C. or lower and 0 kgf / cm ² G or higher and 0.5 kgf / cm ² G or lower Obtaining a reduced pressure steam at a pressure of
By steaming the oyster by injecting the reduced-pressure steam at a steam amount of 0.1 kg / h or more per kg of the oyster to the oyster not immersed in a liquid, the center temperature of the oyster becomes 85 ° C. Maintaining the above state for 1 minute or more;
Including the production method. The production method according to claim 1,
The production method, wherein the steaming step includes a step of reducing the infectivity of norovirus inherent in the oyster. The production method according to claim 1 or 2,
The production method further comprising a step of freezing the steamed oyster obtained in the steaming step. The production method according to claim 3,
The production method, wherein the step of freezing includes the step of freezing the steamed oyster using cold air of -20 ° C or lower. The production method according to claim 4, wherein
The production method, wherein the step of freezing includes the step of freezing the steamed oyster by injecting the cold air to the steamed oyster.   Steamed oysters produced using the production method according to claim 1. An apparatus for producing steamed oysters for steaming oysters,
A boiler for supplying high-pressure steam;
A steam changer that converts the high-pressure steam into reduced-pressure steam;
A steamer for steaming the oyster using the reduced-pressure steam;
A high-pressure steam pipe connecting the boiler and the steam changer;
A reduced pressure steam pipe connecting the steam changer and the steamer;
With
The steam changer is supplied with the high-pressure steam having a temperature of 100 ° C. or more and a pressure of 3 kgf / cm ² G or more into a water tank provided in the steam changer, so that the water in the water tank is changed. boiling 100 ° C. or higher 105 ° C. temperature below and 0 kgf / cm ² G or more 0.5 kgf / cm ² G or less in the vacuum vapor pressure is configured to generate,
The reduced-pressure steam pipe has an inner diameter larger than an inner diameter of the high-pressure steam pipe;
By steaming the oyster by injecting the reduced-pressure steam at a steam amount of 0.1 kg / h or more per kg of the oyster to the oyster that is not immersed in the liquid in the steamer, The manufacturing apparatus which has a steam jet for maintaining the state whose center temperature of the said oyster is 85 degreeC or more for 1 minute or more. The manufacturing apparatus according to claim 7, wherein
A freezer for freezing steamed oysters;
A chlorofluorocarbon supply unit for supplying chlorofluorocarbon to the refrigerator;
Further comprising
The manufacturing apparatus, wherein the refrigerator has a cold air outlet for freezing the steamed oyster by injecting cold air cooled by the chlorofluorocarbon to the steamed oyster with the refrigerator.